So you're not even talking about "mixing"...you're talking about some kind of surround listening system. I'm not even sure what you mean by "ambi system".
Isn't that some kind of Home Theater thing...?
Ambisonic is not surround. It's a way of recording and producing through mathematics (plugins in most cases) other takes of the sound you recorded. You start out with a Tetrasonic mic (4 capsules in a tetrahedron) and record four channels.
You can, after the recording, derive an MS, XY, AB or any other stereo signal. You can also derive 5.1 surround. Or 7.1. Or a 4 channel playback format for theatrical performances. That's "first order".
"Second order" microphones are arriving on the market just now. 8 capsules. 8 channels. The same as before, but with height information.
Both second and first order can be translated into much anything you want, even for headphones. That format was once known as --forgot the English word for it, sorry--
Some examples of mics:
Sennheiser AMBEO(R) VR MIC - Microphone 3D AUDIO capture
Brahma Microphones – Versatile ambisonic recording systems
Core Sound TetraMic
Welcome | Microphones and Processors with unique surround sound capabilities. | SoundField
The last one has been taken over by Rode and has just been released in a Rode version, with Rode capsules, obviously.
Welcome | Microphones and Processors with unique surround sound capabilities. | SoundField
The first commercially available second order mic:
http://www.core-sound.com/default.php
http://soundfield.rode.com/products/dsfbmk2
And we'll soon be seeing Ambi recorders, like the Zylia:
http://www.zylia.co/purchase.html
MEMS mics might just make this technology affordable:
https://www.arkamys.com/affordable-ambisonic-microphones-are-possible/
There's even a cheap Chinese one on the market. But I can't remember the brand and I can't find it atm.
And before anyone asks: no I don't own one. Even the cheapest ones are pretty expensive. But I've experimented with mics I borrowed from a friend who's doing this professionally. And I'm building one atm. First order, 4 electret capsules to start with. There's only one problem left: calibration.
We're all talking about studio mixing...when you sit at the mix position and mix.
That's what the equilateral monitor setup is used for. Being able to hear the mix and the stereo imaging. If you're mixing in one of the surround formats, and then again, there is the triangle and subsequent angles and positions that are most effective for surround mixing, depending on which surround format/number of speakers you are using.
Can you think outside of the box, for a moment?
In Ambisonic setups, you can't always put the speakers in ideal positions. And there is no "standard setup". It's all compensated in the playback system. Some use arrays with over a hundred speakers. For first order, you need minimum four, for second order, you need more. Minimum 6, I think. But since it's all mathematically translated, you can even "mix" it down for headphones.
That's what's happening today. It is already in use, as it's not new. It's based upon the work of Michael Gerzon et al in the seventies. One outcome was quadrophonic, which died commercially because of the fact that most housewives don't want 4 speakers in their living room. And the fact that quadrophonic vinyl was far from ideal and there were three or four competing standards.
But it never went away. The math behind it continued development, in academic circles. It's used in gaming sound, in surround movie sound and in theaters, for artistic performances. And now it's being used to produce sound for virtual reality applications.
It's also used in home recording. By people who record ambiences, nature sound and by people who make electronic music.
It's also already used a lot for music recording. There already have been productions using ambisonic mics, mainly for classical music, but the final output was only stereo. You might have some CD's that have been produced with ambisonic mics, especially if you like choirs. And you've already listened to ambisonic mics when you go to the movies.
Everyone who uses Reaper, can use it today. There are several tools available, from free to expensive.
Once you start to comprehend how you can "move" sound around, you also understand what the problem is with today's mixes. Or, at least, a part of the problem. And that triangle is a small part of the problem. It pins you down in one "perfect" position. Everything outside of that position sounds less. Often far less.
Look at pictures from old studios. Studio's that produced the first stereo, which we all admire. And the engineers who invented some of the tricks we use today. There are no equilateral triangles in most cases.
I'm not saying it is The Homy Grail. But it will provide a crosspoint, enabling recordists to supply a more universal track to the sound engineer who's mixing. And it already provides a way into new formats, for gaming and VR.
Now, for what it means to the OP, who has a loss of low end on the right side because the left is near a wall...
Once you abandon the ideal triangle, you can put the desk in a skewed position, lessening the low end amplification from the left and evening out the differences. It also moves the right speaker closer to the wall, which would lift low end a bit. And then you'll notice that the sweetspot also gets bigger.
It will take time to experiment, or measure. But it can be done.